Extreme pressure lubricant



Sept. 17, 1940. c. F. swlNEHART i EXTREME PRESSURE LUBRICANT l Filed June 1, nasa U L Q .Tw mw v M (mv. V y M v e I .l ,/f

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Y MW 'TTORNEE' I Y Patented Sept. 1940 UNITED STATES EXTREME PRESSURE LUBRIoAN'r Carl F. Swinehart, Cleveland Heights, Ohio, assignor to The Harshaw Chemical Company, Elyria, Ohio, a corporation of Ohio Application June 1, 1938, Serial No. 211,202

6 Claims This invention relates to extreme pressure lubricants and especially to sulfur containing compositions adapted for addition to lubricating, cutting. or drawing oils for the production therein of extreme pressure properties.

' Lubricants `of the extreme pressure class are used where the lubricating requirements are very severe as, for example, for lubricating hypoid gea-rs. Experience has shown that it is impossible to maintain in` a stable solution in lubricating oils as much free sulfur as is required for ,a lubricant of this class. It has, therefore, been customary to add the sulfur, at least in part, in combined form. Residues from sulfur-containing crude oil have been used, also terpene sulfides, sulfurized sperm oil and various thio-ethers. The petroleum residues are objectionable because of impurities and color imparted to the final lubricant while the thio-ethers are object tionably expensive.

` Accordingly, it is the object of my invention to provide a composition overcoming to a remarkable degree these objectionable features of the prior art, that is, to produce a bright, transparent lubricant at a lower cost than with sulfurized terpenes, such as di-pentene or the like and a sulfur composition which may be readily incorporated in any of the commonly used lubricating v oils and to provide a superior process for the v achievement of such results. Other objects will become apparent as the description proceeds.

In the accompanying drawing, Fig. 1 is a freezing point diagram of the ternary system sulfurnaphthalene-aniline and Fig. 2 is a freezing point diagram of the binary system sulfur-naphthalene.

In accordance with the invention, I form a mixture containing sulfur, naphthalene or equivalent and preferably also aniline or equivalent.

such size as would interfere seriously with subsequent incorporation of the composition in oil. The result is a solid composition which I call a sulfur base and which can, at a convenient time, be incorporated in a lubricating or cutting oil by dissolving at a moderately elevated temperature and then heating to a considerably higher temperature for a suitable period of time.

The mixtures of sulfur, naphthalene and ani- This mixture is heated to homogeneity and cooled in a manner to prevent the growth of crystals to- By eutectic is meant the sulfur-naphthalene eu- .tectic line of the three component system, the same being indicated by the reference character E in Fig. 1. I have found that with 20% naphthalene and the remaining made up of any proportion of sulfur and aniline up to 20% or even 30% aniline, the composition can be incorporated in a highly saturated, highly refined Pennsylvania bright stock, which is the oil giving most difficulty in the practice of the invention.

The mixtures of sulfur, diphenyl and aniline are preferably in the following proportions:

Sulfur .Eutectic (about 15%) to 50% Diphenyl Eutecti c (about to 5,0% Aniline 0% to 10% Naphthylamine (alpha or beta) may be s'rubstii tuted for aniline and serves to reduce the amount of naphthalene or diphen'yl required.

Incorporation of the sulfur base in oil may be accomplished by adding the same, in proportion of 1% to 4%, to a suitable body of oil at from C. to 110 C'., with agitation, and, after the mixture becomes homogeneous, elevating the temperature to 13050. to 170 C. for 3 to 6 hours. During this time, a part of the sulfur is believed to react with the oil to form combined sulfur, leaving in the oil-less free sulfur than the maximum amount which will remain in solution therein. These are preferred conditions of incorporation for a paraffin base oil, such as Pennsylvania. Variations may be made without departing from the principle of Athe invention. For mid-continent and western (U. S.) oils, (asphaltic or naphthenic base) the temperature and heating time can be considerably reduced.

Example 1 Parts by weight Sulfur (refined flour) 50 Naphthalene 40 Aniline 10 The naphthalene and aniline were heated to 80 C. When melted, this mixture was added to the sulfur and stirred until cool (40 to 50 C.). Four parts by -Weight of this base were incorporated in parts by Weight of a highly rened, 90 sec. Pennsylvania bright stock, being brought to homogeneity at 100 C. and then cooked for four hours at C. The resulting lubricant showed good extreme pressure properties. The limiting amount of sulfur base which can be used for any given. condition of cooking is determined by the. amount of uncombined sulfur left in the nal product, which should not greatly ex' ceed 1%.

Example 2 Parts by weight Sulfur (rened our) 40 Naphthalene v50 A'nline 10 Mixing and incorporation in the oil were the same as in Example 1. t

Example 3 Parts by weight Sulfur (rened flour) 50 Naphthalene Y i 45 Aniline 5 Compounding and incorporation in oil were the same as in Example 1.

Example 4 Parts by weight Sulfur 30 Diphenol 60 Aniline 10 Example 5 Parts by weight Sulfur 50 Naphthalene Naphthylamine (alpha or beta) 10 Example 6 Parts by weight Sulfur 35 Diphe'nyl 60 Naphthylamine (alpha or beta) 5 The sulfur bases of Examples 4, 5 and 6 may be substituted for those of any of the other examples with good. results.

Dimethyl aniline may be substituted, mol for mol, for aniline in the foregoing examples, altho it is more expensive and therefore less desirable.

The sulfur may be in the form of rened flour, owers, or the like state. Diphenyl maybe regarded as the substantial equivalent of naphthalene and alpha and beta naphthylamine and dimethyl aniline may be substituted for aniline. kOther aryl mon-amines, which term is understood to include methyl and ethyl substituents on the nitrogen atoms, may also be used with more or less satisfactory results.

Having thus described my invention, what I claim is:

1. A' sulfur composition adapted for addition to lubricating oil, the same comprising sulfur, a substance of the group consisting of naphthalene and diphenyl and an aromatic amine of the group consisting of aniline, di-methylaniline and alphaand beta-naphthylamine, said aromatic amine being present in proportion less than sulfur and said sulfur and said aromatic amine together exceeding 50% of the composition by weight.

2. A sulfur composition adapted for addition to lubricating oil for imparting extreme pressure` properties thereto, the same comprising a. mixture of sulfur, naphthalcne and aniline, sul fur being present in excess of the sulfur-nephthalene eutectic mixture for any given aniline content, anline being present to the extent of not more than 20% by weight, and the sulfur content being such that the freezing point of the mixture does not greatly exceed C.

3. A sulfur` compositionv adapted for addition to lubricating oil, the same comprising sulfur, a substance of the group consisting of naphthalene and diphenyl and an aromatic amine of the group consisting of aniline, dimethylaniline and alphaand beta-naphthylamine, the sulfur content being from 30% to 80% by weight andI said aromatic amine being present to the extent of from 5% to 20% by weight.

4. A process of producing an extreme pressure lubricant which comprises dissolving in a lubricating oil a sulfur-naphthalene composition containing more than 30 per cent sulfur and having a Afreezing point not greatly exceeding 95 C. at atemperature of from 90 to 110 C. and then heating the solution at from 130 to 170 C. until the uncombined sulfur content has been reduced to approximately 1% or.less.

5. `Ari extreme pressure lubricant, being the product resulting from dissolving in a lubricating oil of high saturation from l per cent to 4 per cent of a composition comprising more than 30 per cent sulfur, naphthalene and less than 20% of aniline, at a temperature between 90 C. and C. and then heating the resulting material at temperatures between C. and C. whereby to effect reaction of a part of the sulfur with the oil, the uncombined sulfur in the final product being of the order of 1 per cent or less.

6. A process of producing an extreme pressure lubricant which comprises dissolving in a lubricating oil a composition 'comprisingvsulfun a substance of the group consisting of naphthalene and diphenyl, and an aromatic amineof the group consisting of aniline, dimethylaniline, and alphaand beta-naphthylamine, the said composition being dissolved at a temperature of from 90 C. to 110 C. and then heating the solution at from 130' C. to 170 C. until the uncombined sulfur content has been reduced to approximately one per cent or less.

CARL F. SW'INEHART. 

